Triangular strand for cables



Dec. 9, 1952 A. cHAMoUx 2,620,518

TRIANGULAR STRAND FOR CABLES Filed Dec. 19, 1949 [Nl '-ENTOR. @gamin @www ,4 Trams/EVS Patented Dec. 9, 1952 TRIANGULAR STRAND Fon CABLES Alexandre" Chamcux, Bourg, France, assigner to Societe Trellerie & Cablerie de Bourg, Bourg, France, a French joint-stock company ppiication necembe r i9, 1949, serial No. 133,506

In France December 30, 1948 cables of conventional construction. Such cables have the advantage that lfor a 'given cross-sectional area their outer wearingsurface is greater.

Y Inthe known cables the triangular strands lare generally formed on a triangular corewith round wires wound thereon. They triangular core itself is made of wires of Atriangular cross-section, but it has also been proposed Yto form such cores of a strand comprising three round wires (or three elementary circular strands made of round wires) of equal diameter twisted with three intermediate round wires (or strands) of much smaller diameter which are so disposed as tofill the three spaces between the successive wires of larger diameter to form a triangular prole.

A rst object of my invention is to provide a cable formed of triangular strands which cable will contain no triangular profile wire. l

Another object of my invention is to provide a triangular cable strand wherein at least the core will -comprise round wires of the same diameter and wherein each longitudinal edge of the triangular shape will be formed of the same wire through-out its length. l V

Still a further Iobject of my invention is a triangular cable strand rcomprising a core formed of a strand of circular cross-section and of three round wires wound thereon in equally spaced relation.

I may for instance an. axial wire and .with

form a circular strand with six Wires spirally wound thereon. By winding cn such a strand with a g dinerent pitch three equidist-ant wires of the same diameter as the wires of the core there is obtained a compo-site strand having a cross-section in the form of an equilateral triangle with rounded apexes. Such a triangular strand max7 be used as such, or it may preferably form a core whereon there is wound one or several layersof round wires in the known manner. It willalso be understood that the inner circular strand could be formed of several layers of round wires. For instance it may comprise an taxial wire, a `first layer of six wiresfand a second layer of twelve wires. In such a case the three `outer wires must be of a somewhat larger diameter than the wires of th-e inner strand.

In any case the winding pitch of the three outer wires of the triangular strand or core should be equal to the winding pitch of the strand in the fin-a1 cable, as it will be evident, in order that the Strand may .exactly Afill a Sector the cable structure.

In sorne cases I may select the respective diameters of the three wires in such a manner that one side of their triangular outer profile will be somewhat convex to remain parallel to the circular outer profile of the core, while 'the two other sides of the said triangular prole are straight. Such an arrangement is of advantage when such strands form outer members for a larg-er cable to provide for the iinishedcable a cylindrically curved outer surface while leaving straight mutual contacting inner faces for the successive triangular strands forming the cable.

In the annexed drawings:

Fig. 1 is -a. cross-section showing a triangular strand or core established in accordance with my invention.

Fig. 2 shows another embodiment of such `a triangular strand.

Fig. 3 is a side view'of the triangular strand of Fig. 2, the 'successive layers being cut back to show the inner construction of the strand.A

Fig. 4 is a cross-section of a'cable formed of strands of the kind of Figs. 2 and 3.

- Fig. 5 shows another embodiment of my improved triangular stra'nd'.

Fig. 6 illustrates a 'modification of the strand of Fig. 5, wherein one ofthe sides of the triangular prole is convex.

The triangular cofre illustrated in Fig- 1 comprises a circular strand 'o'f conventional construction formed of an axial wire I and of six outer wires 2 disposed around wire l in close regular formation, wires I and 2 being of the same diameter. On the 'circular strand thus formed there is spirally wound a set of three wires 3 in spaced equidistant relation, the said wires 3 being round Iand of the same diameter as wir'e'sl and 2. f The winding pitch of wires *371s much greater than the pitch `of wires 2 in such a manner that wires 3 do not fit int-o the intermediate spaces or depressions between the successive wires 2 but are wound on the circumference which forms: the cuter profile of the strand l--2, subh'circumference being indicated at 4 in Fig. 1.

It will be seen that under such 'conditions wires 3' determine with the core aprole in thelfrm of an equilatera'l triangle 5', the sides 'of such triangle being tangent tc circumference 4. .f

The triangular core thusl obtained is preferably not used as such in the construction of a cable, but there is wound thereon one or several layers of round wires 6 (Figs. 2 and 3) which may be of the same diameter as wires I, 2 and 3 or of another diameter. The winding pitch of these outer layers is of course different from the pitch of wires 3; in the case illustrated it is the lsame 3 as the winding pitch of Wires 2, but this is in no way necessary.

The triangular strand thus established is used in the convention-a1 manner to form a cable by winding a plurality of such strands around an appropriate core with a pitch equal to the pitch of wires 3, six being the number generally selected owing to the equilateral form of the elementary strands. Fig. 4 shows such a cable.

It will be understood that my invention thus permits the construction of a triangular strand cable containing triangular prole wires,v as hitherto generally used. Moreover it is formed of wires having the same diameter, which facilitates manufacture.

In the embodiment of Fig. 5 the triangular strand comprises a circular core formed of nineteen round wires of the 'same diameter, namely: an axial wire I I, a first layer of six wires 12a and a second layer of twelve wires I2b Wound on the first layer with a different pitch, generally with a pitch opposed to the former. On this inner circular strand there are Wound three round wires I3 of'a somewhat larger diameter, such wires being in spaced equidistant relation to determine an equilateral proiile with the sides of the triangle tangent to the circumference of the inner circular core. VThe difference inv diameter between wires I3 and wires Il, I2a or I 2b is relatively small. Of course wires I3 are wound with a pitch different from wires I2b.A

On the triangular strand thus obtained there is wound an outer layer of round wires II.

It is sometimes convenient to have for the strand an outer profile somewhatdeparting from the triangular profile, that is, one side being more or less convex. This is easily obtained by selecting two Wires 231i, of a somewhat smaller diameter than the third one 23h as indicated in Fig. 6. The strand thus obtained has one convex curved side, which is particularly well adapted to form part 0f the outer prole of the iinal cable, as willV be apparentiorthose skilled in the art. The wires 22a, 22h, and 2l in Fig. 6 correspond in arrangement with the wires Y I2a, IZb and I1 of Fig. 5. Y f

Although I have described triangular strands of substantially equilateral profile, it should be understood that by properly selecting the respective diameters of the three wires 3 any other triangular profile may be obtained, for instance corresponding to ve strands in the finished cable, or to more than six. In each particular case I determine-the required triangular `proiile to give a circular outer profile coaxial with the circular proiile of the inner core; and I thereby determine the diameters of the three intermediate wires to be used so as to create the necessary angular portions of these triangular strands which are wound exterior to the core.

I claim:

1. A triangular strand for cables comprising an inner circular core; and three wires of circular cross-section spirally wound on said core in equally spaced relation, said vWires being of @D such a diameter as to determine a triangular outer prole substantially tangent to the circular profile of said core; the inner circular core being formed of a circular strand of Wires, and the outer layer of said circular strand having a Winding pitch substantially different from the pitch of the three wires wound on said inner circular core.

2. A triangular strand for cables comprising an inner circular core; and three wires of circular cross-section spirally Wound on said core in equally spaced relation, said wires being of such a diameter as to determine a triangular outer profile substantially tangent to the circular proleof said core; and an outer layer of wires wound on said three wires with a pitch substantially different from the winding pitch of said three wires.

3. A triangular strand for cables comprising an axial wire, six wires having the same diameter as said axial wire and spirally wound thereon in contacting relation; three wires having the same diameter as said axial wire and spirally wound on said six wires in equally spaced relation and having a `pitch substantially different from the winding pitch of said six wires; and an outer layer of wires wound on said three wires with a pitch substantially different from the winding pitch of said three wires.V

4. A triangular strand for cables comprising an axial wire; six wires having the saine diameter as said axial wire and spirally wound thereon in contacting relation; twelve wires also having the same diameter as said axial wire and spirally wound on said six wires in contacting relation with a pitch substantially diierent from the winding pitch of said six wires; three wires Wound on said twelve wires in equally spaced relation, said three wires being ofA such a diameter as to determine a triangular outer prole substantially tangent to the circular proiile'of the layer formed bysaid twelve wires; and an outer layer of wires wound on said three wires with a pitch substantially different from vthe winding pitch of said three wires.

` 5. A Ytriangular strand for cables comprising an inner circular core and three wires of circular cross-section spirally Wound on said core in equally spaced relation, said three wires being of such respective diameters as to determine an outer proiile in the form of a triangle with two straight sides and a convex side, the said proiile being substantially tangent to the circular prole of said core.

ALEXANDRE CHAMOUX.

, REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS 

